Method and apparatus for forming sand molds



Dec. 4,1923. 1,475,935v

I C. W. COLEMAN METHOD AND APPARATUS FOR FORMING SAND MOLDS Fild Oct. 2, 1922 apparatus in which Patented Dec. '4, 1923.

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reorumne ooMr NY, orirninannnrrrra, 'rnnnsy tvanra aoonron-arron or IBENNSYLVANIA.

' 7 M THonAnn APPARATUS non roma nessnn MOLIDS. v r a Application filed October 2, 192 2.-. Serial No, 591,741,

To all-whom it'ma-yconcerag Be it known that I, CHARLEsW. CoLnMAn, a citizen of the United States, temporarily residing in London,in the county of Middle sex, England, in the Kingdom of Great Britain, have invented certain new and useful Improvements, ratus for Forming Sand'Molds, of which the following is avtrue and exact description, reference being had to the accompanying drawings, which form a part thereof.

My invention relates to the formation of sand molds by the ordinary method and a flask is set over a pattern and sand compacted in the flask and over the pattern to form the mold, the pattern being subsequently withdrawn to leave the mold in condition for use. As heretofore constructed and operated, and particularly where the pattern is one having pockets adapted to form projections in the sand mold, there is more or less frictional resistance to the parting of the sand from the pat tern which sometimes results in the breaking of the sand and particularly of projecting portions of the sand. It i the object of my invention to provide an improved method and apparatus adapted for use with such method whereby the danger of breaking the mold can be obviated or greatly diminished, and, generally speaking, my invention consists in the method of forming such molds in which air under pressure i admitted through the pattern to the face of the sand mold so as to assist in lifting the mold from the pattern and overcoming the frictional resistance which tends to break certain parts of the sand mold and, obviously, where a pattern having pockets is employed, air under pressure is, admitted to the bottom of the pockets so as to support the projections in the sand mold and assist in their withdrawal from the pockets. Mechanical features of my invention consist simply in making provision for the introduction of the air under pressure to the face of the pattern. I

In the drawings which illustrate my invention,

Fi ure 1 is an elevation partly in section showlngthe parts of the molding machine to which my invention is applicable and 1 showing the mold as partly withdrawn from the pattern, and

in Methods and Appa-.

. FigureQ is a face, view of. thenpattern indicatedin Fig. 11 1 v V l T A indicate a portion of the machine on which the pattern plate is supported, this being, as shown, a vibrator frame having a level top edge indicated at A and a compressed air'chamb er A formed below this sage A with means, as, a cock indicated at A for introd chamber A B is a pattern plate resting on the top edge of the frame A and, as is usual, firmly secured to the frame. B B, etc, are air passages formed through the pattern plate 13 and registering, as shown, withsimilar air passage C formed in the pattern which is indicated at@ and which is shown as formed with wide, deep pockets indicated at C, C, etc. D is a flask of ordinary con-- 'struction resting, as is usual, on the flask frame indicated at F. E indicates the sand mold formed in the flask having, as shown, projections E, E, etc., formed in the pocket C" of the pattern, the mold being shown as partly withdrawn from the pattern- In operation, the flask being placed in the proper position'around the pattern plate, the molding sand is compacted in the flask and over the pattern in the usual way. Before, however, its introduction to separate the mold from the pattern,,compressed air, preferably of regulated pressure, is introduced into the compressed air chamber A and finds its way through the air passages 3, C into the bottomrof the pattern pockets C so that'when the flask and pattern are separated, compressed air will act against the bottom of the projections E and assist in the work of lifting them out of the pockets, thus greatly diminishing the tendency of friction to break-0E the projections.

Having now described my invention, what I claim a new and desire to secure by Letters Patent, is:

1. In the formation of sand molds bythe compacting of sand over patterns and subsequently withdrawing the mold so formed from the pattern, the method of facilitating the withdrawal of the mold from the pattern which consists in forcing air under pressure through the pattern into contact with the formed face of the and mold.

' 2. In the formation of sand molds havin projecting parts by the compacting of san ucing compressed air into the top edge and communicating through a pas- V ove'f patterns having pockets" to" ferIn-isuch projections 'and subsequently ithdrawing the mold so formed from the pattern, the me d i 'ee etin the Withdrawal of me d frp th P t ern w icl on s i -4 forcing air underpressure through the pattern into the ockets formed therein and into contact with the the sand mold. v 1 H In a sandmo lding machine comprising connectin I said "chamber with thel sand" 16 I. 4. Ina/sand m ld'ngmechine ccmp rising** projecting parts of the" base" 0f thepatte'rn and ai'ri p esse'gels form'ingf' ace of the pattern;

ing ctions in the send; @5161, the? com-, bination therewith 0 f afcbinpre'ssed air chamber-loca ed? t.1.the besefi he p and air passages connecting said chamber L with the 'bottom floi: the pockets. in th pattern, 7 V 7 C AR ES c 

